Comment 35 for bug 1830747

Reviewed: https://review.opendev.org/663124
Committed: https://git.openstack.org/cgit/openstack/nova/commit/?id=09ec97b95b19a42b949da76fe1f1b3cc06da8f35
Submitter: Zuul
Branch: stable/pike

commit 09ec97b95b19a42b949da76fe1f1b3cc06da8f35
Author: Matt Riedemann <email address hidden>
Date: Tue May 28 13:59:20 2019 -0400

    Add regression recreate test for bug 1830747

    Before change I4244f7dd8fe74565180f73684678027067b4506e in Stein, when
    a cold migration would reschedule to conductor it would not send the
    RequestSpec, only the filter_properties. The filter_properties contain
    a primitive version of the instance group information from the RequestSpec
    for things like the group members, hosts and policies, but not the uuid.
    When conductor is trying to reschedule the cold migration without a
    RequestSpec, it builds a RequestSpec from the components it has, like the
    filter_properties. This results in a RequestSpec with an instance_group
    field set but with no uuid field in the RequestSpec.instance_group.
    That RequestSpec gets persisted and then because of change
    Ie70c77db753711e1449e99534d3b83669871943f, later attempts to load the
    RequestSpec from the database will fail because of the missing
    RequestSpec.instance_group.uuid.

    The test added here recreates the pre-Stein scenario which could still
    be a problem (on master) for any corrupted RequestSpecs for older
    instances.

    NOTE(mriedem): In this version we have to use the MediumFakeDriver
    because change I12de2e195022593ea2a3e2894f2c3b5226930d4f is not
    in Pike so resizing to the same host does not work with the
    SmallFakeDriver.

    Change-Id: I05700c97f756edb7470be7273d5c9c3d76d63e29
    Related-Bug: #1830747
    (cherry picked from commit c96c7c5e13bde39944a9dde7da7fe418b311ca2d)
    (cherry picked from commit 8478a754802e29dffbb65ef363ee189162f0adea)
    (cherry picked from commit a0a187c9bb9bef149e193027a6eedc09ba10ce1f)
    (cherry picked from commit 581df2c98676b6734e8195ab56c9e0dba74789a5)